A multi-channel synthetic aperture radar has been proposed as means for achieving high functionality and high performance of a synthetic aperture radar.
In the case of a multi-channel synthetic aperture radar, if the number of transmitting antennas is one, it is necessary to use a plurality of reception antennas.
At this time, by disposing a plurality of reception antennas along the orbital direction of a platform in which a radar device is mounted, HRWS (High-Resolution Wide-Swath) disclosed by Nonpatent Literature 1 listed below can be implemented. HRWS means high resolution and a wide observation width which make it possible to assume that signals received via a plurality of channels are a received signal via a signal channel, and to separate azimuth ambiguity.
Further, MTI (Moving Target Indicator) disclosed by Nonpatent Literature 2 listed below can be implemented. MTI is a process for detecting a moving target by using correspondences between signals received via channels to remove clutter.
Studies to implement both HRWS and MTI are disclosed by Nonpatent Literatures 3 and 4, and show that when implementing HRWS, a combination of reception antennas with a low correlation among channels is desirable, whereas when implementing MTI, a combination of reception antennas with a high correlation among channels is desirable.
In order to implement both HRWS and MTI which should satisfy such conflicting requirements about a correlation among channels, it is necessary to increase the number of channels and to select a combination of reception antennas with a low correlation among channels and a combination of reception antennas with a high correlation among channels.